This invention is concerned with the provision of a hand tool for storing and for applying O-ring seals, such as for applying O-ring seals to faucet valve stems. Conventionally the upper end portion of a faucet valve stem is of, for example, serrated form comprising a plurality of longitudinally extending spline grooves so that a handle may be non-rotatably mounted on this upper end portion of the valve stem, turning of the handle operatively causing turning of the valve stem with resultant opening or closing of the faucet valve as a result of the action of a lead screw provided on the valve stem. In mounting such a faucet valve stem it is usually necessary for sealing purposes to provide on the valve stem at least one O-ring seal which is disposed at the required position on the valve stem by being manually resiliently expanded and moved along the valve stem over the serrated upper end portion thereof and the lead screw to the required position which is usually constituted by an annular groove between two annular shoulders. However, this procedure of manually disposing the resiliently expanded O-ring seal over the serrated upper end portion of the valve stem and over the lead screw can be relatively time-consuming since it is an awkward and cumbersome procedure, and furthermore since the serrated upper end portion of the valve stem and the lead screw frequently have relatively sharp edges this disposition of the O-ring seal over the serrated upper end portion and the lead screw can result in the surface of the O-ring seal being cut or abraded with the result that when the faucet valve stem is operatively installed there may be leakage of water past the O-ring seal.